On the Rain and Drainage - Waters at Rothamsted. 245 
difference occurs in March, but in all the winter months the 
variation is considerable. On the whole year the small gauge 
shows, on an average, 2'774 inches less rain than the large 
gauges, or a deficiency of 9"8 per cent. 
Some of the causes contributing to this difference between the 
gauges arc tolerably manifest. Thus a heavy snow-fall is much 
better retained by the large gauge than by the small ; the 
deposits of mist, dew, and hoar-frost are also distinctly greater 
with the large sraufje. The increased difference between the 
gauges during the winter months thus admits of explanation, 
while the difference observed during the middle of summer is 
not so easily accounted for. 
The rainfall at Rothamsted for each month and year during 
the twenty-eight years 1853-80 is given in Table II. The 
rainfall for January 1853 is adopted from the records at 
Chiswick, the Rothamsted gauge being not then completed. 
From February 1853 to the end of June 1873 the results given 
are those obtained with the first large gauge. From this date to 
the end of 1874 the results are the mean of those yielded by the 
first and second large gauge. After this date the rainfall is that 
measured by the second large gauge. For certain days on which 
a portion of the rainfall was lost the readings of the small gauge 
have been adopted. For two months, distinguished by brackets 
in the Table, an estimate has been made of the probable rain or 
snow on certain days, no certain record being obtained. 
The average rainfall at Rothamsted during twenty-eight 
years has been 28'302 inches. This rainfall is distinctly 
higher than that usual in the eastern counties of England. In 
the excellent Hyetographical Map, prepared by Mr. G. J. 
Symons for the Sixth Report of the Rivers' Pollution Com- 
mission, it appears that while the rainfall of the eastern counties 
is generally below 25 inches, the rainfall of an isolated district 
comprising part of Hertfordshire, Buckinghamshire, and a 
small portion of Bedfordshire, is between 25 and 30 inches. It 
is in this district of relatively high rainfall that Rothamsted is 
situated. 
We have been kindly supplied with copies of the records of 
rainfall at various stations, situated mostly in the neighbourhood 
of Rothamsted, those stations being selected at which observa- 
tions had been made throughout the twenty-seven years, 1853-79. 
We are indebted to the Rev. C. W. Harvey for copies of the 
records at Gorhambury, St. Albans ; Nash Mills, Hemel 
Hempstead ; and Hitchin : to Mr. J. M'Laren for the record of 
his own observations at Cardington, Bedford ; and to Mr. G. J. 
Symons for copies of the records at Royston, and at Stretham, 
Ely. To compare with these we have also taken the records ot 
